text = String.Format ("{0:00}:{1:00}:{2:000}", minutes, seconds, fraction);
GUI.Label (Rect (400, 25, 100, 30), textTime); //changed variable name to textTime -->text is not a good variable name since it has other use already

}

In your OnTriggerEnter function you then have to write the following to access the time when the trigger was entered (adjust "Main Camera" and "Timer" to whatever your game object and script name are that contain your timer):

I edited the answer to answer your additional question. You add a member variable in your timer script so you can access it from other scripts. You access this variable by finding the game object and script which contains this variable. You do this in your OnTriggerEnter function. More information on this topic can be found in the script reference (http://unity3d.com/support/documentation/ScriptReference/index.Member_Variables_26_Global_Variables.html) or the chapter on game objects and components under the same link